I have just constructed a Jaycar Phoenix card reader for my HTPC and would like feedback regarding the test voltages I'm measuring. In the following list the first figure is what Jaycars instructions say the voltage should be, followed by my measurements:
Between pins 7 & 14 on IC2 and IC3 - 5.0 (6.5)
Pin 2 of IC1 - >8.7 (12)
Pin 6 of IC1 - At least -7.8 (-11.5)
Cathode of D3 - >15.6 (22.1)
Cathode of ZD1 - 13 (17.2)
These measurements were taken with jumpers on 3.5795MHZ and Phoenix, switch in, powered by hard drive connector. No mods. Tried installing in 2 different PC's - same results. Are these higher voltages likely to be a problem? (Would prefer not to cook my card). There were 2 brass pins left over when finished which I could find no reference to in the instructions - are they relevant? I have also noticed that voltages are slightly lower when first powered on, rising slightly with time - is this normal?
I'm an electronics novice (1st project) so any advice would be appreciated, including tests I could perform. Is there a blank card test I could try before risking my 45xx card? Can supply photos if required